Although some halachic decisors have recommended wearing white underwear during the onah of the veset, common practice is to allow the wearing of colored underwear. In most cases, it is advisable to wear colored underwear to provide grounds for leniency with stains. Since the period might begin at this time, however, and it is important to be aware of any staining (even when it does not render a woman niddah), very dark colors are not recommended at this time of the month.